The ankle joints and muscles are very important for various physical functions such as safe ambulation (walking), stair climbing, and for balancing. The ankle joint is capable of a wide range of motion including dorsiflexion and plantar flexion. Dorsiflexion brings the toes upward and closer to the front of the leg and plantar flexion points the toes downward, curling the sole of the foot under and deepening the arch of the foot. In addition, the ankle muscles, tibialis anterior and the gastrocnemius-soleus unit muscle groups, are critical in the proper functioning of the ankle. The tibialis anterior is an extensor muscle of the anterior compartment of the leg which acts to extend the toes and to produce dorsiflexion. The gastrocnemius-soleus unit muscle groups is a prominent flexor muscle group forming the calf muscles. Together with the Achilles tendon, the gastrocnemius-soleus unit muscle group act to lift the heel and to produce plantar flexion.
Therefore, when injury occurs to the ankle joints and muscles it is imperative to rehabilitate and exercise them, if possible, in order to restore stability and range of movement, increase strength, and recover neurological capacities so that the victim of the injury can walk again. This is possible by exercising one ankle, if only one ankle has been injured, or both ankles on a device which is capable of isolating the movement of the ankle or ankles to forward and backward motion and thereby, to pure and isolated dorsiflexion and plantar flexion. In addition, exercising a strong, healthy ankle with a weak ankle at the same time will aid rehabilitation of the weak ankle, if the weak ankle is not capable of these exercises on its own.
One way this can be accomplished is by exercising the muscles surrounding the ankle, lower leg and foot through a desired range of motion on a device that can provide resistance to such movement. Indeed, a frequently neglected muscle group for exercise injury prevention and rehabilitation is the shin. The major muscles responsible for dorsiflexion (i.e., tibialis anterior and extension hallicusis longus) are all present in the shin area. Moreover, by strengthening the muscles in the lower leg and foot, one may significantly reduce the possibility of future ankle injuries. Additionally, by improving strength and range of motion, balance can be improved.
The prior art devices designed to exercise and rehabilitate ankles can be characterized by different tensioning structures capable of movement in various directions. For example, U.S. Pat. No. 5,368,536 discloses an Ankle Rehabilitation Device that is capable of exercising one ankle at a time in multiple directions. This device discloses a plurality of attachment points extending around the perimeter of the foot receiving platform for providing the various directions of exercise. The device also provides a resistance means and an adjustment means to vary the resistance. However, this device only exercises one ankle at a time, strapped by straps and does not allow the user to use a strong ankle and foot to assist the weak ankle and foot in the therapy. Moreover, the device utilizes a complex two bar linkage mounted at one end to the base plate and at the other end to one of a plurality of attachment points on the foot receiving platform where a coilspring is operatively connected between the bars of the linkage to adjust the resistance on the machine and does not provide an adjustment means to vary the resistance by adjusting the location of the foot location on the foot receiving platform relative to the pivot point.
Prior art device U.S. Pat. No. 5,891,002 discloses an orthopedic device comprising a foot board, pivot means, and fastening means allowing exercise boards mounted on a roller that is secured to the assembly by a retainer pin allowing the user to use “active assistance” where a strong ankle and foot to assist the weak ankle and foot in the therapy. However, this device does not provide a function to add additional resistance to the device to continue therapy using the device once the weak ankle is strong enough to require additional resistance to continue rehabilitation.
Prior art device U.S. Pat. No. 7,364,534 discloses an exercise device for providing resisted movement of the ankle through the full range of motion thereof to exercise the muscles in the ankle, foot, lower leg and especially shin area. This exercise device comprises: (a) a base; and (b) a foot receiving member having an ankle section. The foot receiving member is mounted on the base for resisted pivotal movement about: (1) a substantially horizontal axis extending transversely and underneath the ankle section of the foot receiving member; and (2) a substantially vertical axis extending from the base and through the ankle section of the foot receiving member. However, this device only exercises one ankle at a time, and does not allow the user to use a strong ankle and foot to assist the weak ankle and foot in the therapy. Moreover, the device utilizes frictional pads to adjust the resistance on the machine and does not provide an adjustment means to vary the resistance by adjusting the location of the foot location on the foot receiving platform relative to the pivot point.
Accordingly, there is a need for a single therapeutic rehabilitation device which can be utilized to strengthen the muscles of the ankle, foot and lower leg for users who injuries may be so severe that active assistance is needed during the rehabilitation process, as well as users further along in the recovery process, where additional resistance is needed to further advance recovery.
Additionally, there is a need for a therapeutic rehabilitation device where resistance adjustment can be achieved by adjusting simply and economically through adjustment of the location of the foot restraints relative to the pivot point on the device, thereby alleviating the need to purchase multiple pieces of equipment and reduce the storage area required for the equipment.
Furthermore, there is a need for a therapeutic rehabilitation device where resistance can be grade-able or measurable, to track the status and progress of the patients during rehabilitation.
Finally, there is a need for a therapeutic rehabilitation device where resistance compact and portable for ease of storage.